Résumé
Fruitlet Core Rot is one on the main disease that affects pineapple fruit development in the world. However, factors promoting the disease are not well known. A large survey, including soil, climatic, physiological and pathological variables at a field scale, and including spatial heterogeneity and temporal variability, was designed and conducted in the pineapple production area in Martinique. This on farm-approach allowed the identification and specification of the main factors responsible for the disease.
Fruit sampling analysis revealed the Penicillium funiculosum was involved in 95% of the observer cases. However, although P. funiculosum was widespread in the soils of-the survey, no quantitative relation was established between the quantity of inoculum in the soil or on the plant and the development of P, funiculosum in fruits.
Fruit observations at harvest time showed a high level of variation between fruits within a field. However, significant correlations between the percentage of infected fruits within a field, the average number of spots per fruit and their size were established.
A global analysis of the data showed that average ascorbic acid content in fruits at harvest is negatively linked with the percentage of infected fruits. The nutritional status of the plants, especially low levels of calcium and magnesium, and/or high levels of nitrogen, is also a significant promoting factor for the development of the disease.
It is concluded that Fruitlet Core Rot in Martinique is promoted by a combination of factors which determine the sensitivity of fruits. Climatic conditions before harvest, acid content, and nutritional status are the main factors.